1. Field of the Invention
The present invention relates generally to an electromagnetic relay and, more particularly, to a relay including a coil member carrying a winding and having an axial cavity within which extends an elongated armature, at least one pole plate projecting into the coil member for interaction with the armature, a yoke arrangement positioned essentially outside of the coil member, and a restoring spring secured to the coil member and connected to the armature to bias the armature to a quiescent position.
2. Description of the Related Art
German Patent No. AS 11 90 103 discloses a relay having a coil member with an axial cavity within which is an armature. However, the armature does not directly serve for electrical contacting. From the contrary, a contact spring is actuated by the armature and the contact spring interacts with a separate contact member. In the known relay, the coil member is composed of two shell-like portions forming a closed protective housing, and two lamellae serving as pole plates are enclosed therein together with the contacting parts so that adjustment of the relay is not possible after assembly. The parts are aligned in one shell-like housing portion before assembly. When the coil member is of a ceramic material, as proposed in the German Patent the required stability for retaining the pre-assembly adjustment is to some extent guaranteed. When, however, the coil member is made of a relatively thin-walled plastic in order to miniaturize the relay, then deformations of the coil member after assembly can be effected, particularly when applying the winding. It is, thus, not guaranteed that the pre-assembly adjustment setting and the functional reliability of the relay will be retained when the relay coil member is formed of plastic for miniaturization.
German Published Application No. OS 20 59 390 also discloses a multiple contact structure, wherein, for a two part base member, a plurality of pairs of pole plates are arranged in one plane in one housing part and are surrounded with glass frit. The same problem as set forth above would also arise in this case if the housing where fabricated of thin-walled plastic.